Class Type Parameters

[Hans-Eric Grönlund]

Ah, you're right. I should have been more specific. 

What I wanted to do was to imitate a ruby-method that accepts a code block, runs it and retries n times if an exception is thrown. Like the ruby-method, I wanted to let the user decide what type of exception to catch by giving it as an argument. I explain it in more detail on my weblog:

http://www.hans-eric.com/2008/01/17/loop-abstractions-in-d/

For that reason, I guess the compile time solution (templates) is to prefer in this case, although as a user of the function, I would have preferred a non-template syntax.

Like this

retryable(SomeExceptionClass, args...);

over this

retryable(SomeExceptionClass)!(args...);


Cheers!


Jarrett Billingsley Wrote:

> "Hans-Eric Grönlund" <hasse42g at gmail.com> wrote in message 
> news:fmnv6b$1hi6$1 at digitalmars.com...
> > Cool, not exactly what I was looking for, but I can use it to solve the 
> > problem - a little differently than I'd expected.
> >
> > Just out of curiosity: In Delphi (Object Pascal) one can assign a class 
> > type to a variable, like so:
> >
> > type
> > TAClass = class
> >  ...
> > end;
> >
> > TAClassClass = class of TAClass;
> >
> > procedure do_something_with_class(AClass: TAClassClass);
> > begin
> >  ...
> > end;
> >
> > Can something similar be done in D?
> 
> Depends on what you want to do.  Do you want to do compile-time stuff?  Then 
> templates are the way to go.  Do you want to something at runtime with the 
> class?  Then RTTI is the way to go.  typeid(AnyTypeReally) gets you an 
> instance of the TypeInfo class which is automatically generated for every 
> type in your program.  Runtime introspection and stuff is currently really 
> weak in D, since the compile-time stuff is (usually) sufficient, more 
> expressive, and faster.
> 
> "What do you want to _do_?" is probably the most important question here. 
> Asking how to mechanically translate a piece of code from another language 
> into D is not necessarily the best way to go about it, especially if the 
> source language is one that not many people have experience with (Delphi is 
> _reasonably_ popular but I doubt many people here have used it). 
> 
>